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PUBLIC HEALTH ASSESSMENT

FAIRCHILD AIR FORCE BASE
SPOKANE, SPOKANE COUNTY, WASHINGTON


PATHWAYS ANALYSIS/PUBLIC HEALTH IMPLICATIONS

A. Introduction

The following section discusses the various contaminants ofconcern, how people might come into contact with thesecontaminants and the potential health effects that mayresult. In order for an exposure to these contaminants tooccur, all the elements of an exposure pathway must be inplace. Exposure pathways are divided into completed andpotential and can be current, past or future. A completedexposure pathway consists of five elements: source,environmental media/transport, point of exposure, route ofexposure and receptor population. A potential exposurepathway exists when some but not all of these five elementsare present and the potential exists that the missingelement(s) have been present, are present or will be present. The completed and potential exposure pathways forFairchild are given in Tables 2 and 3 below. Each pathway is then discussed in terms of thecontaminants of concern and the potential health hazard posed.

    Evaluating Non-cancer Risk

In order to evaluate the potential for non-cancer adverse health effects to result from exposure tocontaminated media (i.e., air, water, soil, and sediment), a dose is estimated for each contaminantof concern. These doses are calculated for situations (scenarios) in which nearby residents or on-base workers might come into contact with the contaminated media. The estimated dose for eachcontaminant under each scenario is then compared to ATSDR's minimal risk level (MRL) or EPA'soral reference dose (RfD). MRLs and RfDs are doses below which non-cancer adverse healtheffects are not expected to occur (so called "safe" doses). They are derived from toxic effect levelsobtained from human population and laboratory animal studies. These toxic effect levels can beeither the lowest observed adverse effect level (LOAEL) or a no-observed adverse effect level(NOAEL). In human or animal studies, the LOAEL is the lowest dose at which an adverse health effect is seen, while the NOAEL is the highest dose that did not result in any adversehealth effects.

Because of the uncertainty in these data, the toxic effect level is divided by "safety factors" givingthe lower and more protective MRL or RfD. If a dose exceeds the MRL or RfD, this indicates onlythe potential for adverse health effects. The magnitude of this potential can be inferred from thedegree to which this value is exceeded. If the estimated exposure dose is only slightly above theMRL or RfD, then that dose will fall well below the toxic effect level. The higher the estimateddose is above the MRL or RfD, the closer it will be to the toxic effect level.

    Evaluating Cancer Risk

Some chemicals have the ability to cause cancer. Cancer risk is estimated by calculating a dosesimilar to that described above and multiplying it by a cancer potency factor, also known as thecancer slope factor. Some cancer potency factors are derived from human population data. Othersare derived from laboratory animal studies involving doses much higher than are encountered in theenvironment. Use of animal data require extrapolation of the cancer potency obtained from thesehigh dose studies down to real-world exposures. This process involves much uncertainty. Currentthinking suggests that there is no "safe dose" of a carcinogen and that a very small dose of acarcinogen will give a very small cancer risk. Cancer risk estimates are, therefore, not yes/noanswers but measures of chance (probability). Such measures, however uncertain, are useful indetermining the magnitude of a cancer threat since any level of a carcinogenic contaminant carriesan associated risk. The validity of the "no safe dose" assumption for cancer-causing chemicals isnot clear. Some evidence suggests that certain chemicals considered to be carcinogenic mustexceed a threshold of tolerance before initiating cancer.

This document describes cancer risk qualitatively using terms like low, very low, slight and nosignificant increase in cancer risk. These terms can be better understood by considering thepopulation size required for such an estimate to result in a single cancer case. For example, a lowincrease in cancer risk indicates an estimate in the range of one cancer case per ten thousandpersons exposed over a lifetime. A very low estimate might result in one cancer case per severaltens of thousands exposed over a lifetime and a slight estimate would require an exposedpopulation of several hundreds of thousands to result in a single case. DOH considers cancer riskto be not significant when the estimate results in less than one cancer per one million exposed overa lifetime. The reader should note that these estimates are for excess cancers that might result inaddition to those normally expected in an unexposed population.

Cancer is a common illness that increases with age. Depending on the type of cancer, anunexposed population could be expected to have a substantial number of cancer cases. There aremany different forms of cancer that result from a variety of causes. About a quarter of the people in Washington State die of cancer. Approximately one quarter to one third of people living in the United States will develop cancer at some point in their lives.

    Multiple Exposure and Toxicological Mixtures

A person can be exposed by more than one pathway and to more than one chemical. Exposure tomultiple pathways occurs if a contaminant is present in more than one medium (i.e., air, soil,surface water, groundwater, and sediment). For example, the dose of a contaminant receivedfrom drinking water may be combined with the dose received from contact with that same contaminant in soil.

It is much more difficult, however, to assess exposure to multiple chemicals. In almost everysituation of environmental exposure, there are multiple contaminants to consider. The potentialexists for these chemicals to interact in the body and increase or decrease the potential for adversehealth effects. The vast number of chemicals in the environment make it impossible to measure allof the possible interactions between these chemicals. Individual cancer risk estimates can beadded since they are measures of probability. When estimating non-cancer risk, however,similarities must exist between the chemicals if the doses are to be added. Groups of chemicalsthat have similar toxic effects can be added such as volatile organic compounds (VOCs) whichcause liver toxicity. Polycyclic aromatic hydrocarbons (PAHs) are another group of chemicalsthat can be assessed as one added dose based on similarities in chemical structure and metabolites. Although some chemicals can interact to cause a toxic effect that is greater than the added effect,there is little evidence demonstrating this at concentrations commonly found in the environment.

The following evaluations do not rely solely on whether the estimated dose of a contaminantexceeds its health comparison value or acceptable cancer risk level. Factors such as backgroundexposure, a growing scientific data base and the inherent uncertainty in assessing health risk areconsidered when formulating conclusions. These evaluations are based on current data andsubject to change should more data become available relative to the site and/or the toxic potentialof the contaminants.

Table 2.

COMPLETED EXPOSURE PATHWAYS FOR FAIRCHILD AIR FORCE BASE, WASHINGTON

#Pathway
Name
ContaminantSourceMediaPoint of
Exposure
Route of
Exposure
Exposed
Population
Persons
Exposed b
TimeHealth Risk
Non-cancer Cancer

Comments

1aCraig RoadLandfillTCE, Nitrate aCraig RoadLandfill
(SW-8)
GroundwaterVietzke Villagewater supply wellsIngestion
Skin contact
Inhalation
Vietzke Villageresidents1000PastLowSlightWater supply wellsabandoned. Past exposureof concern.
Airway Heightswater supply wells Ingestion
Skin contact
Inhalation
Airway Heightsresidents4000PastNoNotSignificantLow levels of TCE.Current monitoring.
2000Current
4000Future
Scafco watersupply wellsIngestionScafcoemployees50PastNoNotSignificantWater supply wellsabandoned.
1bCraig RoadLandfillVOCCraig Road
Landfill
(SW-8)
AirOutdoor air nearVietzke VillageInhalationVietzke Villageresidents1000Past NoNotSignificantLow levels of VOCs.Current monitoring.
200Current
1000Future
2WastewaterLagoonsTCEWastewaterLagoons
(WW-1)
GroundwaterWest Thorpe Roadresidential wells Ingestion
Skin contact
Inhalation
West ThorpeRoad residents100PastNoNotSignificantLow levels of TCE.Current monitoring.
50Current
100Future
3 No-NameDitch(FairchildEasement)TPH, MetalsWastewaterlagoons
(WW-1)
Surface water
Sediment
No-Name Ditch(FairchildEasement)Ingestion
Skin contact
West ThorpeRoad residents100PastNoNotSignificantNo comment.
50Current
100Future
4TordonApplicationTordon
(Picloram)
No-NameDitch,
County Route902
GroundwaterWest Thorpe Roadresidential wells Ingestion
Skin contact
West ThorpeRoad residents100Past NoNotSignificantNo comment.
Surface water
Soil
No-Name Ditch
County Route 902
Ingestion
Skin contact
West ThorpeRoad residents<100Past NoNotSignificantNo comment.
5On-baseActivitiesVOC, TPH,PCB, metalsP-1, P-2 and
AOC sites
Sediment/SoilP-1, P-2 and
AOC sites
Ingestion
Skin contact
Dustinhalation
On-baseworkers200PastNoNotSignificantAreas of contaminationinfrequently accessed.
100Current
200Future
LeadSW-11SoilSW-11Ingestion
Skin contact
Dustinhalation
On-baseRecreators200Past NoNotSignificantLow levels of lead in soil.
100Current
200Future

a = Nitrate is discussed in this pathway relative to the Vietzke Village supply wells but is not thought to be related to the Craig Road Landfill.
b = The number of persons exposed is an estimate base on demographic data obtained from ATSDR and other sources.

Table 3.

POTENTIAL EXPOSURE PATHWAYS FOR FAIRCHILD AIR FORCE BASE, WASHINGTON

# Pathway
Name
Contaminant Source Environmental
Media
Point of
Exposure
Route of
Exposure
Exposed
Population
Time Comments
1 Future Off-Base Development VOC SW-8, WW-1, FT-1 Groundwater NA Ingestion
Skin contact
Inhalation
Residents, workers Future Groundwater on abutting property is not suitable for domestic use.
2 Future On-Base Development VOC, TPH Priority-1, 2 and 3 sites Groundwater NA Ingestion
Skin contact
Inhalation
Workers Residents Future Groundwater in many areas of the base is not suitable for domestic use.
Soil NA Ingestion
Skin contact
Residents Future Some on-base areas are currently not suitable for high exposure activities (e.g., residential development).
3 Base Supply Well #2 VOC, TPH NA Groundwater Base Residential and Building Taps Ingestion
Skin contact
Inhalation
Base workers and residents Future Site SW-13 (EOD range) represents a potential source of groundwater contamination.
NA = Not applicable. These components are not currently present.

B. Completed Exposure Pathways

Completed exposure pathways are discussed below. A summary, background, health assessment,conclusions, and recommendations are provided for each pathway. The health assessment isseparated into a discussion of non-cancer and cancer effects.

Pathway 1a: Craig Road Landfill --> Groundwater --> Vietzke Village Residents/Airway Heights Residents/Scafco Employees

SUMMARY

The Craig Road Landfill is the source of TCE groundwater contamination that has been found inVietzke Village public supply wells and the Scafco Corporation facility supply well. It is also apossible source of TCE contamination in the Airway Heights public supply wells.

    Vietzke Village Residents

The supply wells for the Vietzke Village are officially abandoned and no longer a source ofexposure. Past exposure to TCE in Vietzke Village drinking water represents no apparent publichealth hazard to the general population. However, an indeterminate public health hazard existsfor the children of women exposed while pregnant to TCE in Vietzke Village drinking water priorto August 1989 when exposure ceased. Children born to women who drank Vietzke Villagewater while pregnant prior to August 1989 could have been at some risk for birth defects or otheradverse birth outcomes. There is no clear evidence, however, to indicate that the levels of TCEexposure at Vietzke Village were high enough to cause these types of health effects.

Past exposure to nitrate in Vietzke Village drinking water represents no apparent public healthhazard to the general population. Levels of nitrate in the Vietzke wells could have causedmethemoglobinemia in infants only if additional risk factors were present such as stomachinfection, diarrhea or high dietary nitrate intake. An indeterminate health hazard exists for thechildren of women exposed while pregnant to nitrate in Vietzke Village drinking water. Inconclusive evidence suggests that levels of nitrates similar to those found in the Vietzke wellscan cause adverse birth outcomes.

    Airway Heights Residents

Current and past exposure to TCE in the Airway Heights public supply wells represents noapparent public health hazard. The Airway Heights public supply wells continue to be monitoredby the base and show very low levels of TCE that are below regulatory standards.

    Scafco Employees

The supply wells for the Scafco Corporation are officially abandoned and no longer a source ofexposure. Past exposure to TCE in the Scafco Corporation supply wells represents no apparentpublic health hazard.

BACKGROUND

The Craig Road Landfill covers approximately 100 acres of base property along Craig Roadapproximately 0.7 miles south of U.S. Route 2 and 0.5 miles east of the main base. Operated asthe main landfill for the base from the late 1950s through the late 1970s, it received variouswastes including sanitary refuse, industrial waste, and construction debris. The RemedialInvestigation/Feasibility Study completed for the Craig Road Landfill in September 1992described two specific source areas within the landfill: the northeast area covering approximately6 acres and the southwest area of about 13 acres. Both areas received waste via trench-and-fill atdepths greater than 30 feet. A third area covering about 30 acres in the southeast corner isthought to have received only inert, solid materials (e.g., concrete). In addition to the fill areas,the landfill was also the site of the base sanitary wastewater treatment plant. This plant receivedsanitary wastewater from housing units and the base hospital as well as industrial waste frommaintenance shops. Treated water was discharged to a surface evaporation/percolation pond andto underground trenches. Occasionally, treated wastewater was spread on the fill areas to helpcompact the waste. The treatment plant ceased operation in November 1993 (see Figure 5).

A substantial remedial effort has been undertakento address volatile organic compounds (VOCs) in groundwater originating from the two identifiedsource areas of the landfill. A geo-textile liner(cap) now covers the landfill to prevent rainwaterinfiltration that could carry more contaminants intothe groundwater. Also, a groundwater pump-and-treat system was installed in September 1995 andis currently operating at the site to removecontaminants from groundwater and preventmovement to off-base areas.

The Craig Road Landfill is the source of groundwater contamination that has affected VietzkeVillage public water supply wells and Scafco Corporation water supply wells. The landfill is alsoa potential contributing source of the groundwater contamination currently affecting AirwayHeights public supply wells. Groundwater flow is estimated to be moving east/northeast from thelandfill in both the shallow (alluvial) and bedrock (basalt) aquifers. Bedrock groundwater in thisarea is part of the Wanapum Basalt aquifer and is divided into an upper flow region (Basalt A)and deeper flow region (Basalt B) by a layer of mostly impermeable sedimentary rock (InterbedA). Bedrock groundwater flow in the Craig Road Landfill area was measured at a range of 0.3-8.6 feet per day for Basalt A and 8 feet per day for Basalt B.

Most of the contamination detected in and aroundthe landfill has been found in the upper Basalt Abedrock flow. Interbed A is not completelyimpermeable, however, and can allow groundwaterand contaminants to move into the deeper Basalt Bflow. It is possible, therefore, for contaminants tomove from the ground surface of the landfill throughthe shallow aquifer into the Basalt A flow and thenthrough fractures into the deeper Basalt B flow. TheBasalt B region of the Wanapum Basalt aquifer isseparated from the deeper Grande Ronde Basaltaquifer by another layer of sedimentary rock(Interbed B). No drinking water or monitoring wells in this area are located in the Grand Ronde aquifer.

Figure 6 shows the outline of a TCE plume moving from the two identified source areas in thelandfill. In April 1991, a maximum of 2,800 ppb TCE was detected in monitoring well MW-85located in the Basalt A bedrock flow just across the north perimeter of the landfill. The maximumcontaminant level (MCL) for TCE is 5 ppb. Although several other VOCs were detected in soilgas samples, TCE is the only groundwater contaminant migrating off-base at levels of concern. TCE originating from the landfill has impacted drinking water wells at the Vietzke Village trailerpark, Scafco supply wells and possibly the Airway Heights public supply wells. These threepoints of exposure are discussed below.

HEALTH ASSESSMENT

    Vietzke Village Residents

Vietzke Village is a 55-60 unit trailer park located along the northeast border of the Craig RoadLandfill. The land originally contained only one residence until 1968 when the trailer park wasstarted. Drinking water for trailer park residents was formerly supplied by three blended, openbore-hole wells (RW-9, RW-10 and RW-11) located on the park grounds as indicated in Figures 5and 6. According to the owner, the wells were installedbetween the late 1960s and early 1970's. RW-11 servedas the primary source of drinking water for VietzkeVillage. RW-10 and RW-9 were primarily used forirrigation and laundry but also served as drinking watersupply wells during times of high use. Specifics on thetype and rates of water use from these wells are notavailable.

Initial sampling and analysis for VOCs in July 1989detected only TCE at a maximum level of 80 ppb in well RW-9. The most recent sampling inJune 1991 detected maximum levels of TCE at 59 ppb (RW-11) and tetrachloroethylene (PCE) at0.6 ppb (RW-9). Fairchild provided bottled drinking water to residents of the park from July, 18through early August 1989 when the park was connected to the Fairchild water supply. 14 Allthree wells were officially abandoned between May and June 1993. The TCE sampling results for the Vietzke wells are given in

Table 4. below.

Vietzke Village Supply Well TCE Measurements

Well July
1989*
June
1990
April
1991
June
1991

RW-960/80782243
RW-1030/2757NS47
RW-1140/51795259

* Two values represent duplicate samples.
NOTE: Wells no longer in use as of August 1989.

TCE is the only contaminant of concern related to the Craig Road Landfill that has been detectedin the Vietzke wells. However, nitrate was also found at elevated levels in the Vietzke watersupply. Samples taken between September 1982 and May 1988 showed elevated nitrates with amaximum of 10.5 ppm detected in January 1986. It is not know from what point in the Vietzkewater distribution system these samples were taken. A maximum of 19.2 ppm nitrate was alsodetected in monitoring well MW-80 located in the Vietzke Village trailer park. Although thesource of this nitrate contamination is unknown, the RI noted that MW-80 is located near theVietzke septic field. Septic fields, landfills and agricultural runoff are common sources of nitratecontamination in drinking water wells. In general, only shallow wells are at risk for nitratecontamination. However, the improperly cased bedrock wells at the Vietzke Village weresusceptible to contaminants moving from the shallow aquifer. Nitrate levels detected inmonitoring wells located near the landfill indicate that the landfill is not a substantial source ofnitrate.

There is currently no exposure of Vietzke Village residents to TCE or nitrate in drinking watersince water is now supplied by the base. Past exposure occurred via ingestion, skin contact andinhalation of vapors (TCE only). Exposure via ingestion ceased when the base supplied residentswith bottled drinking water. Inhalation of TCE vapor ceased when the village was supplied withbase water.

Specific contributions of each well to the overall drinking water supply are not available. Tapwater samples were reportedly taken from Vietzke Village residences but this data could not belocated. In order to be protective of public health, it was assumed that Vietzke Village residentswere exposed to the maximum level of TCE detected in the primary supply well (RW-11 at 79ppb). Exposure to nitrates was estimated using the maximum level detected of 10.5 ppm. Theperiod of concern for past exposure of Vietzke Village residents could have extended from 1968when the trailer park first started through July 1989 whenexposure ceased.

Additional exposure of Vietzke residents to TCE occurred as aresult of landfill emissions from soil into air. The dose receivedfrom breathing TCE in air emitted directly from the landfill wascalculated using estimated air levels derived from mathematicalmodels. The contribution of this pathway to the overallexposure of Vietzke residents to TCE is very small and does notaffect the dose comparisons made below. Current and pastexposure of Vietzke residents to landfill gases is addressedseparately as completed exposure pathway 1b (page 28).

      Non-Cancer Effects

    Trichloroethylene (TCE)
    Past exposure to TCE in Vietzke Village drinking water is not expected to pose a non-cancerrisk for the general population. There is a concern that children born to women who drankVietzke Village water while pregnant prior to August 1989 could have been at some risk forbirth defects and other adverse birth outcomes. There is no clear evidence, however, toindicate that the levels of exposure at Vietzke Village were high enough to cause these typesof health effects. There is no current exposure to TCE in drinking water at the VietzkeVillage.

    The estimated dose from the maximum level of TCEdetected in primary supply well RW-11 (79 ppb) isbelow ATSDR's acute oral minimal risk level (MRL)for TCE. This means that short-term exposure (i.e.,less than two weeks) is not of concern. EPA has notprovided a chronic oral reference dose (RfD) and nointermediate or chronic oral MRLs are available withwhich to evaluate longer-term exposure to TCE. Apreviously available intermediate oral MRL for TCEhas been withdrawn as of November 1997. Thepotential for non-cancer health effects from longer-termexposure was based, therefore, on available data fromhuman and animal studies.

    One animal study determined that rats exposed to high doses of TCE in drinking water whilepregnant gave birth to offspring with heart defects. Although this study has been criticized, itrepresents the most sensitive toxic endpoint of TCE exposure and is supported by limitedevidence in humans. 15 The lowest-observed adverse effect level (LOAEL) from this studywas compared with the estimated dose received by a pregnant woman exposed to 79 ppb TCEin drinking over a 9-month period. The estimated dose was approximately 35 times belowthis LOAEL. This dose was based on an assumption of 2 liters of drinking water ingested perday combined with an equivalent dose from skin absorption and inhalation of TCE as a resultof showering, bathing and other indoor water use. This comparison indicates that TCE in theVietzke wells would not have been of concern.

    It is important to consider, however, that some human studies have associated TCE exposurewith birth defects in children as a result of exposure prior to birth (i.e., in utero exposure). The birth defects identified included heart malformations, neural tube defects and oral clefts. Other adverse birth outcomes reported include decreased fetal weight and increased fetaldeath. The levels at which pregnant mothers were exposed in these studies are not welldefined. Some exposures appear to have been substantially higher than the levels measured atVietzke Village while others are similar. These studies are suggestive of an associationbetween TCE exposure and developmental effects but are not sufficient to allow an accurateestimate of what the risk might have been for Vietzke Village residents. Further study mayshow no association between the levels of TCE in the Vietzke wells and developmentaleffects. More discussion of the non-cancer effects of TCE is given in the ToxicologicalSummaries section (page 51).

    Also of concern is the potential that levels of TCE in the Vietzke wells may have been higherin the past. Although no data exists prior to July 1989 when these wells were first sampled,levels of TCE may have been higher in the past. Each of the three supply wells is locatedapproximately 800 feet downgradient of monitoring well (MW-85) that showed considerablevariation in TCE levels with no established trend. Such variation could also have occurred inthe Vietzke wells. Since an exposure duration as short as the first trimester of pregnancycould be of concern, short-term increases in TCE levels could be important. Any fluctuationsin the Vietzke wells, however, would not likely have reached levels found in MW-85 becauseof the expected dilution of TCE moving from Basalt A into uncontaminated water from the relatively clean Basalt B aquifer.

    The suggestive nature of the humans studies associating TCE in drinking water with birthdefects, along with the possibility that exposures may have been higher prior to initialsampling, is cause for concern. Babies born to women who drank Vietzke water whilepregnant prior to August 1989 may have been at risk for birth defects and other adverse birthoutcomes. The small and transient nature of the population at Vietzke Village make it anunlikely candidate for a study aimed at evaluating birth defects. Any residents living atVietzke Village during the period of concern (1968 through July 1989) can contact RobertDuff (DOH) toll-free at 1-888-5TOXICS (1-888-586-9427) or ATSDR at 800-447-1544 formore information.

    Nitrate
    Nitrate in Vietzke Village drinking water is not expected to result in non-cancer health effectsto the general population. Exposure of infants to formula prepared with Vietzke Villagedrinking water prior to August 1989 could have resulted in methemoglobinemia only ifexposure was accompanied by other risk factors such as stomach infection, diarrhea or highdietary nitrate intake. An indeterminate health hazard exists for the children of womenexposed while pregnant to nitrate in Vietzke Village drinking water. Inconclusive evidencesuggests that levels of nitrates similar to those found in the Vietzke wells can cause adversebirth outcomes.

    The estimated dose for an infant ingesting 0.6 liters per day of formula prepared with 10.5ppm nitrate contaminated water is equivalent to the RfD for nitrate. This RfD is based on astudy that found no methemoglobinemia in infants at drinking water levels below 10 ppmwhile 2 % of the infants exposed at 11-20 ppm showed early clinical signs of this disorder. Most studies show that levels below 20 ppm will not result in symptoms or adverse healtheffects unless accompanied by a large dietary source or simultaneous exposure to bacteria thatcan enhance the conversion of nitrate to nitrite in the digestive tract. 16

    Nitrate-induced methemoglobinemia is caused by decreased oxygen delivered to body tissueby the blood and is directly related to the conversion of nitrate to nitrite in the body. Infantsare more susceptible to nitrates in drinking water because of a relatively high fluid intake andincreased levels of fetal hemoglobin compared with older children and adults. Fetalhemoglobin is more easily converted to methemoglobin than is the adult form. At very highlevels of exposure, the decreased oxygen availability to the tissues can cause a seriouscondition called "blue baby" syndrome. This syndrome is often difficult to diagnose but isindicated by a bluish color around the lips, hands and feet. Other symptoms can includelethargy, sweating, flushed skin, vomiting and diarrhea that are easily confused with othercommon ailments. "Blue baby" syndrome can be diagnosed directly by measuring the amountof methemoglobin in the blood. Death can result if severe cases are not recognized. 17

    Some animal studies have shown a relationship between adverse birth outcomes and nitrate indrinking water but only at high doses. 18 A LOAEL was derived from a study that foundimpaired neurobehavoiral development in rats given relatively low doses of nitrate in uteroand as pups. An estimated dose for a pregnant women drinking water from Vietzke Village at10.5 ppm nitrate is approximately 20 fold lower than this LOAEL. This comparison suggeststhat the level of nitrate in Vietzke water would not have been a concern for developmentaleffects. Such a comparison assumes dietary intake and nitrate/nitrite metabolism are similarbetween the rat and human.

    There is some human evidence that pregnant women who drink nitrate contaminated water areat risk for adverse birth outcomes. A recent study showed that nitrate levels above 20 ppmmay be associated with increased spontaneous abortions. 19 Another study showed asignificant increase in birth defects associated with nitrate in drinking water at 5-15 ppm. 20 The latter association could not be attributed solely to nitrate exposure since other chemicalsincluding pesticides were likely present in the drinking water. These and other studiesexamining the relationship between nitrate in drinking water and birth defects remaininconclusive. 17,21,22

    Although there is no conclusive evidence indicating that the level of nitrate in Vietzke Villagedrinking water would have been of concern for the developing fetus, the concurrent exposureto TCE should be considered. Inconclusive evidence suggests that both contaminants mayadversely impact the developing fetus. More research is needed to establish or refute thispotential health effect. Both of these contaminants are widespread in drinking watersupplies across the country, indicating that more research is warranted.

      Cancer Effects

    Trichloroethylene (TCE)
    Discussions with residents indicate that the population of the trailer park is quite transient withmany residents staying less than one year. No significant cancer risk is expected for VietzkeVillage residents exposed for only a few years to the maximum level of TCE detected inprimary supply well RW-11 (79 ppb). A slight increase in cancer risk is expected for thoseresidents exposed for many years at this level. This slight increase in cancer risk wascalculated for a 30-year period of a child growing to adulthood exposed TCE in drinkingwater via ingestion, skin contact and inhalation. If levels of TCE in the Vietzke wells werehigher in the past, this cancer risk would increase.

    TCE was previously classified by EPA as a Group B2 probable human carcinogen based onadequate animal data and insufficient human data. This classification has since been removed,however, and is pending further review. Quantitative cancer assessment was, therefore,performed based on animal data provided by EPA prior to the ongoing review. 23 AlthoughEPA has withdrawn its former classification of TCE as a probable human carcinogen,evidence shows that high doses of TCE can cause lung, liver and kidney tumors in animals. Some human studies suggest a link between TCE in drinking water and leukemia. TheInternational Agency for Research on Cancer (IARC) recently classified TCE as probablycarcinogenic to humans (Group 2A). 24 The cancer effects of TCE are discussed further in theToxicological Summaries section (page 51).

    DOH also performed a crude comparison of cancer rates in the Vietzke Village zip code (i.e.,99022) with statewide rates. Cancers associated with exposure of animals and humans toTCE were examined including lung, liver, kidney/bladder and leukemia as wells as totalcancers. A slight elevation in lung cancer was found (21 cases observed versus 14.2expected). The reason for this increase is not known but is unlikely to be related to TCEexposure. There was no indication that any other types of cancer were elevated.

    This type of comparison is limited in its ability to find small increases in cancer within theexposed population for two main reasons. First, the size of the population within the exposedzip code is too small to detect an increase in cancer at the very low rates estimated. Second,not everyone within the zip code was exposed which could mask an actual increase within theexposed population. The results and limitations of this analysis are discussed further in theHealth Outcome Data section (page 55).

    Nitrate
    EPA has not classified the cancer potential of nitrates. There is evidence that the body canconvert nitrite into cancer-causing nitrosamines. It has been postulated, therefore, that nitratein drinking water could lead to increased cancer risk via conversion into nitrite and thesubsequent formation of nitrosamines. Exposure of rats to nitrite in drinking water along withconcurrent exposure to nitrosable amines has been shown to cause an increase in digestivetract tumors attributed to the formation of nitrosamines in the body. However, this increasewas not seen in rats exposed to nitrate and nitrosable amines. In addition, no increase intumor formation was seen in rats exposed separately to these nitrosamine precursors. Severalhuman studies have failed to provide clear evidence to support a link between nitrate exposureand cancer. 17

    Cancer risk resulting from nitrate in drinking water would thus depend on several factorsincluding the total amount of nitrate/nitrite ingested, the conversion of nitrate to nitrite, theconversion of nitrite to nitrosamine and the cancer potency of the resulting nitrosamine. Thedifficulty in assessing these variables currently prohibits a quantitative estimate of cancer riskfrom nitrate exposure. The average adult daily intake of nitrate from dietary sources isestimated at 73 mg/day. The amount of nitrate formed daily inside the body is estimated to beapproximately equal to this amount. The additional daily intake estimated for an adultdrinking the maximum level of nitrate detected in the Vietzke wells is 21 mg/day. 17 Considering the lack of clear evidence associating nitrate in drinking water with cancer andthe relatively limited contribution from the Vietzke wells to the overall daily dose of nitrate(i.e., 13%), nitrate exposure from Vietzke drinking water is not expected to result in a significant increase in cancer risk.

    Airway Heights Residents

    As groundwater moves east from the Craig Road Landfill past Vietzke Village, it reaches andepression into which shallow and Basalt A bedrock groundwater flows from all directions. Thedeeper Basalt B bedrock flow also enters this channel before continuing east. This depressedshallow aquifer channel, therefore, serves as a barrier against contaminants reaching wells to theeast that are in the shallow or Basalt A bedrock flow. It is likely that contaminants in the Basalt Bflow are substantially diluted and not a threat to impact deep bedrock wells further east. AirwayHeights public supply wells RW-1and RW-4 are located in this shallow aquifer depression (Figure6). Currently, water from these wells is blended with that from a third supply well (Well #5)before being routed to a storage tank that serves the city's water needs. A fourth supply well(Well #7) was recently developed by the city at the corner of Russel and McFarlane. This well isconnected to the water line supplying the storage tank but reportedly gives inconsistent yields. No VOCs were detected in a sample taken from Well #7 in March 1997. 25

    TCE has been consistently detected in RW-1 and RW-4 at low levels. A blended sample fromthese two wells is taken four times per year as part of the base residential well sampling plan. Themost recent sampling in June 1997 detected a maximum of 0.7 ppb TCE. The maximum TCElevel ever found in these wells is 3.2 ppb detected in February 1995. Airway Heights residentsand workers are currently being exposed to TCE in drinking water through ingestion, skin contactand inhalation of vapors. It is likely that the level of TCE exposure is less than the amount foundin RW-1 and RW-4 samples since the output from these wells is mixed with that of Well #7 andWell #5 which have no history of TCE contamination.

        Non-Cancer Effects

      Non-cancer adverse health effects are not expected to result from current or past exposure toTCE in the Airway Heights public drinking water supply. The estimated dose resulting fromexposure via ingestion, skin contact and inhalation to the maximum level ever detected in theAirway Heights public supply wells (3.2 ppb) is 900 times below the LOAEL. This dose wascalculated assuming a 9-month exposure of a pregnant woman drinking 2 liters of water perday combined with an equivalent dose from skin absorption and inhalation as a result ofshowering, bathing and other indoor water use. This LOAEL is based on developmental heartdefects in rats and represents the most sensitive health effect yet found in animal studies.

      Some studies of people exposed to TCE in drinking water indicate a potential association withbirth defects. The levels of TCE are much higher in these studies than those to which AirwayHeights residents were exposed. Further discussion of the non-cancer effects of TCE is given in the Toxicological Summaries section.

        Cancer Effects

      No significant cancer risk is estimated to result from current or past exposure to TCE in theAirway Heights public drinking water supply. A dose was estimated using the maximum levelof TCE (3.2 ppb) ever detected in Airway Heights public water supply. Exposure viaingestion, skin contact and inhalation was assumed to occur over a 30-year period of a childgrowing to adulthood. The estimated cancer risk calculated for this scenario was determinedto be insignificant. The cancer effects of TCE are discussed in the Toxicological Summaries section.

    Scafco Employees

    The Scafco Corporation facility is located at the intersection of Craig Road and McFarlane Roaddirectly east of the southern portion of the Craig Road Landfill. This facility is currently beingleased to a tenant business. Residential well RW-7, installed in April 1974, supplied all waterneeds for this facility until August 1992 when RW-7A was drilled. RW-7A was used as the watersupply well for the facility from sometime after installation on August 13, 1992, until June 1996,when the company connected to the Airway Heights public water supply. The base notifiedScafco of TCE contamination in this well on October 26, 1992. Immediately following thisnotice, bottled drinking water was provided to workers at the Scafco facility and all taps werelabeled as non-drinkable. 26, 27

    Initial sampling of RW-7 in July 1989 detected TCE at 2 ppb and this level was not exceededthrough the final sample round in March 1996 which detected no VOCs. RW-7A has consistentlycontained elevated levels of TCE with an initial detection of 15 ppb in September 1992. Amaximum level of 63 ppb TCE was detected in November 1995. The most recent sampling ofRW-7A in March 1996 detected TCE at 0.67 ppb. Exposure of workers to low levels of TCE atthe Scafco facility occurred via ingestion of drinking water from RW-7 for a maximum durationof 18 years (1974-1992). Ingestion of higher levels of TCE from RW-7A drinking water mayhave occurred over a maximum period of 2 months. Inhalation and skin exposure via showeringand bathing are not considered as routes of exposure for these workers.

        Non-Cancer Effects

      Non-cancer adverse health effects are not expected to result from past exposure to TCE inthe Scafco water supply wells. Workers were assumed to be exposed to 2 ppb TCE viaingestion of drinking water from RW-7 at a rate of 2 liters of water ingested per day. Theestimated dose resulting from this exposure is 2,800 times below the LOAEL. This estimateddose assumed a worst-case scenario of a pregnant woman exposed over a 9-month period andso will be protective of all workers. This LOAEL is based on developmental heart defects inrats and represents the most sensitive health effect yet found in animal studies.

      Some studies of people exposed to TCE in drinking water indicate a potential association withbirth defects. The levels of TCE are much higher in these studies than those to which Scafcoworkers were exposed. Further discussion of the non-cancer effects of TCE is given in the Toxicological Summaries section.

      The possibility exists that exposure of Scafco workers increased to 15 ppb TCE in drinkingwater for the period from August 13, 1992 to October 26, 1992. The estimated dose at thislevel of exposure would still be well below the LOAEL and is at the lower end of theexposure ranges estimated in the human studies described above. Also, lower exposures areexpected in the workplace versus home setting because of increased use of water at home(e.g., showering, cooking). This increased period of exposure is, therefore, not expected tohave resulted in adverse health effects for Scafco workers.

        Cancer Effects

      No significant cancer risk is estimated to result from past exposure to TCE in Scafco watersupply wells. Workers were assumed to be exposed to 2.0 ppb TCE via ingestion of drinkingwater from RW-7 for 18 years at a rate of 2 liters of water ingested per day. The estimatedcancer risk calculated for this scenario was determined to be insignificant. The possibilityexists that exposure of Scafco workers increased to 15 ppb TCE in drinking water for theperiod from August 13, 1992 to October 1992. This potential short-term increase in exposureis expected to have no significant impact on cancer risk. The cancer effects of TCE arediscussed in the Toxicological Summaries section.

CONCLUSIONS

Vietzke Village Residents
No current public health hazard exists for the residents of the Vietzke Village trailer park throughthe use of drinking water. Use of the formerly contaminated water supply wells that served thepark was discontinued in August 1989 when the park was connected to the Fairchild water supply.

Past exposure to TCE and nitrate in Vietzke Village drinking water represents no apparent publichealth hazard to the general population. However, an indeterminate public health hazard existsfor the children of women exposed while pregnant to TCE and nitrate in Vietzke Village drinkingwater prior to August 1989 when exposure ceased. Children born to women who drank VietzkeVillage water while pregnant prior to August 1989 could have been at some risk for birth defectsand other adverse birth outcomes. There is no clear evidence, however, to indicate that the levelsof exposure at Vietzke Village were high enough to cause these types of health effects.

Airway Heights Residents
No apparent public health hazard exists for residents of Airway Heights using the public watersupply. Very low levels of TCE are currently being detected in the city water supply. Ingestionand inhalation of TCE from drinking water at these levels is not expected to cause healthproblems. The Airway Heights public water supply is monitored by the base four times per year.

Scafco Employees
No apparent public health hazard exists for employees exposed to TCE in drinking water whileworking at the Scafco Corporation facility. Low-level exposure of workers to TCE via ingestionof drinking water occurred for some period of time between April 1974 and August 1992 whenthe facility was connected to the Airway Heights water supply.

RECOMMENDATIONS

ATSDR and DOH recommend continued quarterly monitoring of the Airway Heights publicsupply wells for VOCs until three quarterly samples have shown no detections for base-relatedcontaminants. Testing of these wells for VOC contamination can then return to annual samplingas required for all public supply wells. Detection limits for VOCs should be at or below MethodDetection Limits required under EPA Method 524.2.

The base investigated a previous DOH recommendation to sample residential wells RW-32 andRW-49 for possible VOC contamination. These wells are either non-existent or not in-use.

Pathway 1b: Craig Road Landfill --> Air --> Vietzke Village Residents

SUMMARY

No outdoor (ambient) air sampling data are available for any areas of the base. The potential forVOCs to volatilize from Craig Road Landfill soil into outdoor air was assessed using amathematical model. Results from this model indicate that levels of VOCs in outdoor air at thenearby Vietzke Village pose no apparent public health hazard. The Spokane County Air PollutionControl Authority (SCAPCA) currently requires periodic monitoring of emissions from the CraigRoad Landfill. Annual averages of contaminant emissions are used to model ambient air levels atthe perimeter of the landfill to insure that these emissions do not pose a public health hazard. SCAPCA is currently evaluating recent landfill emission data and will require further action ifannual averages exceed a level of concern.

BACKGROUND

No outdoor (ambient) air sampling data are available for any areas of the base. Concentrations inair of some VOCs detected in soil gas at the Craig Road Landfill were estimated for locations atthe perimeter of the landfill including the Vietzke Village trailer park. These estimates were madeas part of the RI/FS for the Craig Road Landfill using EPA's SCREEN air dispersion model(Version 1.1) and maximum concentrations of benzene, TCE and methylene chloride detected inlandfill soil gas. Point source air sampling data associated with the landfill's groundwatertreatment facility and methane vents are available from the Spokane County Air Pollution ControlAuthority (SCAPCA).

HEALTH ASSESSMENT

Modeled air concentrations for the Vietzke Village trailer park indicate that past levels of someVOCs in air off-gassing from the Craig Road Landfill may have resulted in a very low increase incancer risk for residents of the trailer park. This estimated risk was primarily due to TCE andbenzene although some carcinogenic VOCs found in soil gas were not included in the model. It islikely that this model substantially overestimates past air concentrations at the trailer park since ituses maximum soil gas concentrations and worst-case 1-hour averages rather than annualaverages. Annual averages are recommended for use in cancer risk assessment and are expectedto be 10 times lower than 1-hour averages. The model also assumed worst-case weather conditions.

      Non-Cancer Effects

    Non-cancer effects are not expected to result from exposure of Vietzke Village residents tolevels of TCE in ambient (outdoor) air. The TCE ambient air level predicted for the VietzkeVillage is 50 times below the intermediate MRL for inhalation exposure. This MRL is basedon decreased heart rate and sleep effects in rats following high levels of exposure to TCE inair. The additional exposure of Vietzke Village residents from landfill emissions of TCE wasalso considered in combination with the oral and inhalation exposure evaluated for TCE indrinking water. The added exposure estimated by the model was determined to add only asmall percentage to the overall dose. The potential for non-cancer health effects from pastexposure of Vietzke Village residents to TCE in drinking water is discussed as completedexposure pathway 1a (page 16).

      Cancer Effects

    Considering the very low cancer risk estimated by this model and its potential foroverestimation of that risk, it is likely that past levels of VOCs in outdoor air near the VietzkeVillage trailer park did not significantly increase cancer risk. The reader should be awarethat people living in the Vietzke Village for many years prior to August 1989 were exposed toTCE in drinking water at levels estimated to pose a slight increase in cancer risk. Thisexposure is discussed as completed exposure pathway 1a (page 16). In addition to thisestimated cancer risk, DOH performed a crude analysis of cancer incidence in the VietzkeVillage zip code (i.e., 99022). Of all the cancer types evaluated only lung cancer showed anincrease when compared with statewide rates. It is unlikely that this slight increase in lungcancer is related to TCE exposure. The results and limitations of this analysis are given in theHealth Outcome Data section (page 55). The cancer effects of TCE are discussed further inthe Toxicological Summaries section (page 51).

Measurements of VOCs currently being emitted from the landfill are made on a regular basis inaccordance with SCAPCA requirements. Samples are taken from four methane vents and theintake and output of the two air stripping towers. These towers work to "strip" VOCs fromextracted groundwater into air that is then cleaned of the VOC contaminants prior to dischargeinto the atmosphere. Amounts of VOCs emitted from the landfill are monitored to ensure thatyearly average concentrations estimated for off-site locations are below levels of concern asestablished by SCAPCA. SCAPCA uses EPA's SCREEN air dispersion model (Version 3.0) topredict annual average concentrations at locations outside of the landfill. If modeled airconcentrations exceed acceptable annual averages, further investigation will be carried out by theDepartment of Ecology under the Controls for New Sources of Toxic Air Pollutants rule (WAC173-460) as mandated by the Washington Clean Air Act (70.94 RCW).

CONCLUSIONS

No apparent public health hazard exists for the residents of Vietzke Village from inhalation ofvolatile contaminants off-gassing from the Craig Road Landfill. Air emissions are likely todecrease as contaminants degrade and are removed from the groundwater beneath the landfill.

RECOMMENDATIONS

No recommendations are necessary with respect to this pathway. Emissions from the landfill aremonitored on a regular basis.

Pathway 2: Wastewater Lagoons --> Groundwater --> West Thorpe Road Area Residents

SUMMARY

The base wastewater lagoons are the apparent source of TCE groundwater contamination that iscurrently impacting residential wells in the West Thorpe Road area. Exposure of West ThorpeRoad area residents to current levels of TCE in drinking water represents no apparent publichealth hazard. Monitoring of residential wells should continue in this area.

BACKGROUND

Groundwater contamination has been identified in the area east of the wastewater lagoons (WW-1) located on the eastern border of the base along Rambo Road (Figure 7). Groundwater isestimated to be moving east/southeast in this area. WW-1 consists of two wastewater lagoons, askimming pond, and a holding lagoon. The skimming pond receives runoff from the storm waterdrainage system that at one time included discharge from 54 oil/water separators. Many of theseseparators received industrial wastes from base maintenance shops. Historical observations havenoted oil sheens in the lagoons and drainage ditches indicating that many of these separators werenot operating properly. At some point, several separators were redirected to discharge to thesanitary sewer system. In 1991, a major upgrade of the remaining separators resulted in removal,replacement or cleaning of those separators still discharging to the storm water drainage system. A groundwater pump-and-treat system installed in February 1996 is currently operating in theWW-1 area with extraction wells extending southeast towards the anticipated edge of the plume.

HEALTH ASSESSMENT

TCE is the only contaminant of concern affecting residential wells in the West Thorpe Road area. A plume containing primarily TCE appears to be moving east/southeast from the WW-1 site andis currently impacting residential wells in the West Thorpe Road area. The exact source of thisplume has not been determined but is estimated to be in the vicinity of monitoring well MW-102(Figure 7).

The maximum level of TCE ever detected in the WW-1 area is 280 ppb found in on-basemonitoring well MW-102 in February 1991. The maximum level of TCE ever detected off-basein the WW-1 vicinity is 69 ppb found at MW-120 in December 1995. The most recent samplingof monitoring wells at the WW-1 site in June 1997, detected an on-base maximum of 190 ppb inWP-03 and an off-base maximum of 45 ppb TCE in MW-120. MW-120 is an off-base shallowwell located approximately 800 feet east of the WW-1 site that has shown increasing levels ofTCE since initial sampling detected 18 ppb in April/May 1991. MW-122 is a Basalt A bedrockwell adjacent to MW-120 that has shown only minimal TCE contamination suggesting that theplume remains in the shallow aquifer at this point (see Figure 7). Other contaminants, notcurrently impacting residential wells, are discussed under potential exposure pathway (page 44).

Residential wells in the West Thorpe Road area are currently being monitored for VOCcontamination by the base. TCE is the only contaminant of concern detected in residential wellsin this area with a maximum of 1.5 ppb found in RW-13. The most recent sampling of these wellsin June 1997 detected a maximum TCE level of 1.1 ppb in RW-23. 28 Some West Thorpe Roadarea residents are currently being exposed to low levels of TCE in drinking water through ingestion, skin contact and inhalation of vapors.

      Non-Cancer Effects

    Non-cancer adverse health effects are not expected to result from current or past exposure toTCE in West Thorpe Road area drinking water wells. The estimated dose resulting fromexposure via ingestion, skin contact and inhalation to the maximum level (1.5 ppb) everdetected in the West Thorpe Road area drinking water wells is 1900 times below the LOAEL.This dose was calculated assuming a 9-month exposure of a pregnant woman drinking 2 litersof water per day combined with an equivalent dose from skin absorption and inhalation as aresult of showering, bathing and other indoor water use. This LOAEL is based ondevelopmental heart defects in rats and represents the most sensitive health effect yet found in animal studies.

    Some studies of people exposed to TCE in drinking water indicate a potential association withbirth defects. The levels of TCE are much higher in these studies than those to which AirwayHeights residents were exposed. Further discussion of the non-cancer effects of TCE is given in the Toxicological Summaries section (page 51).

      Cancer Effects

    No significant cancer risk is estimated to result from current or past exposure to TCE in theWest Thorpe Road area drinking water wells. A dose was estimated using the maximum levelof TCE (1.5 ppb) ever detected in West Thorpe Road residential wells. Exposure viaingestion, skin contact and inhalation was assumed to occur over the 30-year period of a childgrowing to adulthood. The estimated cancer risk calculated for this scenario was determinedto be not significant. The cancer effects of TCE are discussed in the Toxicological Summaries section (page 55).

    In addition to the estimated cancer risk, DOH performed a crude analysis of cancer incidencein the West Thorpe Road zip code (i.e., 99022). Cancers associated with exposure of animalsand humans to TCE were examined including lung, liver, kidney/bladder, and leukemia as wellas total cancers. No elevations in these types of cancers were detected when compared withstatewide rates except for a slight elevation in lung cancer (21 cases observed versus 14.2expected). The reason for this increase is not known but is unlikely to be related to TCEexposure.

    This type of comparison is limited in its ability to find small increases in cancer within theexposed population for two main reasons. First, the size of the population within the exposedzip code is too small to detect an increase in cancer at the very low rates estimated. Second,not everyone within the zip code was exposed which could mask an actual increase within theexposed population. The results and limitations of this analysis are discussed further in theHealth Outcome Data section (page 55).

CONCLUSIONS

No apparent public health hazard exists for West Thorpe Road area residents using private wellsfor drinking or any other purpose. Very low levels of TCE are currently being detected in WestThorpe Road area residential wells. Ingestion and inhalation of TCE from drinking water at theselevels is not expected to cause health problems. Residential drinking water wells in the WestThorpe Road area are currently monitored by the base on a quarterly basis.

RECOMMENDATIONS

Current monitoring of residential wells in the West Thorpe Road area should continue until thesewells are no longer threatened by groundwater contaminants associated with the base. DOH willconsider a well to be safe after three quarterly samples have shown no detections for base-relatedcontaminants. Detection limits for VOCs should be at or below Method Detection Limitsrequired under EPA Method 524.2.

Pathway 3: No-Name Ditch (Fairchild Easement) --> Sediment/Surface Water --> West Thorpe Road Area Residents

SUMMARY

No-Name Ditch (also known as the Fairchild Easement) runs from the base wastewater lagoons(WW-1) across Rambo Road and through several residential properties. The wastewater lagoonscurrently receive surface water runoff from the base storm water discharge system. This systemformerly delivered waste discharge from base maintenance shops to the lagoons. The ditch is anexposure point for children who might play in and around it during the summer months. Noapparent public health hazard exists for children who currently play in and around No-NameDitch. Although past levels of petroleum-related contaminants in ditch sediment and surfacewater could have been higher, exposure was probably infrequent and not of concern.

BACKGROUND

No-Name Ditch originates on-base at the wastewater lagoons (WW-1) located on Rambo Road. The wastewater lagoons consist of a skimming pond and a holding lagoon. The ditch carrieseffluent from the skimming pond east/southeast across Rambo Road through residential propertieson West Thorpe Road before discharging to a field where the water infiltrates into the ground. The skimming pond receives input from the base storm water drainage system. Before dischargeinto the ditch, this effluent is skimmed with a surface boom that directs water to the holdinglagoon. Discussions with residents in the West Thorpe Road area revealed that flooding of thisditch occurs frequently in the winter months and can be aggravated by obstructions such asexcessive weed growth. Observations by base personnel indicate that water is present in the ditchthroughout the year except in times of drought. A public comment received from a resident statesthat the ditch contains water year round even in times of drought. Residents living along the ditchhave recalled visible contamination in the past including oil sheens. One resident claims that the ditch was once set on fire by local children.

HEALTH ASSESSMENT

Several rounds of surface water and sediment sampleswere taken from the ditch between October 1986 andDecember 1991. The contaminants of concern found inoff-base ditch surface water and sediment during thisperiod are listed in Table 3, Appendix C. Total petroleumhydrocarbons (TPH) were detected at a maximum of 22ppm in off-base ditch surface water and 860 ppm insediment. The final round of ditch sampling conductedduring the RI in November 1991 detected lower levels ofTPH with a maximum of 0.4 ppm in surface water and120 ppm in sediment. No TPH were detected in two off-base ditch samples taken in October 1995. 29

Several metals are listed as contaminants of concern for this pathway. Maximum values of thesemetals exceeded either their respective screening value or estimated background levels in surfacewater or sediment. However, the mean values calculated for the last round of sediment samplingin the ditch (November 1991) indicate that none of metals listed was consistently detected at anelevated level.

Residents recreating in and around the ditch could be exposed to contaminants in surface waterand sediment via accidental ingestion and skin contact. Children reportedly use the ditch forrecreation in the summer as noted by base personnel. 21 A ponded area is located along the ditchnear a residential property. Anecdotal evidence indicated that this small pond is stocked forrecreational fishing. Further inquiry with the owner of the property revealed that small, non-recreational fish are occasional thrown into the pond but are never caught or eaten. There is noevidence to indicate that anyone uses the ditch for fishing. Exposure to ditch contaminantsthrough the ingestion of fish is, therefore, not of concern.

      Non-Cancer Effects
      Metals

    Non-cancer adverse health effects are not expected toresult from current or past exposure of residents toinorganic substances (metals) in No-Name Ditch. Theestimated dose calculated for a child exposed viaingestion of and skin contact with maximum detectedlevels of metals in ditch sediment did not exceed anyMRLs or RfDs. It was assumed that an older child mightplay in and around the ditch 120 days per year over aperiod of 10 years. No MRLs or RfDs are currentlyavailable with which to compare estimated doses to magnesium or aluminum. The 90thpercentile values of these two metals derived from the final round of sampling in the ditch inNovember 1991 do not exceed the 90th percentile background levels published by Ecology. 30 Exposure to magnesium and aluminum in ditch sediment and surface water will not, therefore, result in substantial exposure.

      Total Petroleum Hydrocarbons (TPH)

    Non-cancer adverse health effects are not expected to result from current exposure ofresidents to TPH. There is no MRL or RfD for the group of petroleum-related compoundsknown as TPH. Ecology has adopted a surrogate approach for assessing the potential healtheffects resulting from exposure to TPH. 31 This means that the RfD of a chemical of similarstructure is used to evaluate the total dose of TPH. The dose calculated for a child exposedduring play to maximum levels of TPH found in off-base ditch sediment and surface waterdoes not exceed the surrogate RfD. It should also be noted that maximum levels of TPHdetected in off-base ditch sediments decreased from an initial maximum of 860 ppm to 120ppm in November 1991 followed by no detections in October 1995.

    Past exposure of children or adults to contaminants in ditch surface water and sediments mayhave been higher. Discussions with residents indicate that in the past oil sheens could be seenon the surface water. One resident commented that the surface water in the ditch was ignitedby area children. The operation of approximately 25 oil/water separators at the base prior totheir upgrade in 1991 may well have been faulty. 6 Poor maintenance of these separatorswould have allowed the movement of jet fuel spills and leaks through the base drainagesystem into the wastewater lagoons and then to No-Name Ditch. The bulk of contaminationin the ditch was likely jet fuel. Analysis of surface water and sediment for old fuel spillcontamination is reported as TPH. TCE is another major on-base contaminant but would nothave been expected to reach levels of concern at any time in the ditch because of rapidvolatilization from surface water.

    The potential for adverse health effects from past exposure is dependent on the amount ofTPH present and the frequency and duration of exposure to ditch surface water and sediment. Areas of the ditch with petroleum contamination at levels of concern would likely have beenvisible and avoided. Occasional exposure of persons contacting TPH in ditch surface waterand sediment in the past is not considered a health concern. TPH is discussed further in theToxicological Summaries section.

      Cancer Effects

    No significant cancer risk is estimated to result from current or past exposure tocontaminants in No-Name Ditch. Arsenic is the only carcinogenic contaminant found atelevated levels in the ditch. A dose was estimated for a recreator exposed via ingestion of andskin contact with maximum levels of arsenic detected in off-base surface water and sedimentin the ditch. It was assumed that an older child growing to adulthood could be exposed over aperiod of 25 years. The cancer risk calculated from this dose estimate is very low. This risk isnot considered to be significant since it is approximately equivalent to the risk calculated fornaturally occurring background levels of arsenic in residential yard soil. In addition, it isunlikely that anyone would have such extended contact with the ditch. This evaluation,therefore, should be protective of all possible exposure scenarios.

    In addition to the estimated cancer risk, DOH performed a crude analysis of cancer incidencein the West Thorpe Road zip code (i.e., 99022). Arsenic was the only cancer-causingcontaminant of concern found in the ditch. The type of skin cancer associated with arsenicexposure is not malignant and not tracked by the state cancer registry. Therefore, only acomparison of total cancers was performed. No elevation in total cancers was detected whencompared with statewide rates. The results and limitations of this analysis are given in theHealth Outcome Data section (page 55).

CONCLUSIONS

No apparent public health hazard exists for children playing in No-Name Ditch (FairchildEasement). Ingestion of and skin contact with contaminants in sediment and surface water areestimated to be below a level of concern.

RECOMMENDATIONS

No recommendations are necessary with respect to this pathway.

Pathway 4: Tordon --> Groundwater/Soil --> West Thorpe Road Area Residents

SUMMARY

The herbicide Tordon was applied to roadways in the West Thorpe Road area and No-NameDitch. In 1979, low levels of Tordon were detected in residential garden soil, drinking waterwells, and No-Name Ditch surface water. No apparent public health hazard exists from pastexposure of West Thorpe Road area residents to Tordon in drinking water, surface water or soil.

BACKGROUND

Tordon was applied repeatedly to No-Name Ditch from1966 to 1978 in efforts by the base and the Spokane CountyRoad Department to control weed growth in the ditch. Theherbicide was also used on county roads and rights of waythat may have included West Thorpe Road. Complaints byWest Thorpe Road area residents about affected gardencrops prompted the Washington Department of Agricultureto sample residential drinking water wells in January 1979. Use of Tordon was banned in the West Thorpe Road area inJune 1979, following detection of Tordon in these wells. 32

HEALTH ASSESSMENT

In January 1979 the Washington Department of Agriculturesampled surface water, soil, groundwater and cow's milk inthe West Thorpe Road area. Groundwater samplingrevealed Tordon contamination in several residential wells (maximum at 13.2 ppb), Fairchild on-base supply well #2 (maximum at 0.33 ppb) and the Airway Heights water supply (maximum at1.73 ppb). Tordon was also detected at a maximum of 0.16 ppb in No-Name Ditch surface waterand in residential garden soil at a maximum of 15.0 ppb. A single sample of cow's milk from ananimal grazing in the West Thorpe Road area revealed no Tordon. West Thorpe Road arearesidents were exposed in the past to Tordon in drinking water, soil, and surface water via ingestion and skin contact.

      Non-Cancer Effects

    Non-cancer health effects are not anticipated to result from past exposure of West ThorpeRoad area residents to Tordon in drinking water, surface water or soil. A dose wasestimated for a child chronically exposed to maximum levels of Tordon in drinking water(13.2 ppb), soil (15.0 ppb) and surface water (0.16 ppb) via ingestion and skin contact. It wasassumed that an older child could be simultaneously exposed to Tordon in soil, surface water,and drinking water for 10 years. The resulting estimated dose was 55 times below EPA's RfDfor picloram (active ingredient in Tordon). The RfD is based on increased liver weight in ratsfed high doses of picloram in their diets. 33 Tordon toxicity is discussed further in the Toxicological Summaries section (page 51).

      Cancer Effects

    Considering the low cancer potency of picloram (active ingredient in Tordon) in animals andthe lack of any increase in liver cancer incidence in the exposed area, no significant increasein cancer risk is expected for West Thorpe Road area residents as a result of Tordonexposure. EPA has not yet classified the ability of Tordon to cause cancer in humans. Evidence exists that picloram ) can cause benign liver tumors in female rats. However, noincreases in malignant cancer were evident in rats or mice of either sex tested in this study. Aswith all animal testing for cancer, the doses used to generate these tumors in mice wereextremely high compared with the type of environmental exposure experienced by WestThorpe Road area residents. The cancer effects of picloram are discussed further in theToxicological Summaries section (page 51).

    A quantitative estimate of the cancer risk associated with the Tordon exposure of WestThorpe Road residents was not possible because a cancer potency factor for picloram has notbeen derived. DOH did, however, perform a crude comparison of cancer rates in the WestThorpe Road zip code (i.e., 99022) with statewide rates. The small amount of data availableindicates that liver tumors were caused by high doses of picloram fed to rats. Therefore, livercancer as well as total cancer incidence was examined. No elevations in these types of cancerswere detected when compared with statewide rates. The results and limitations of thisanalysis are given in the Health Outcome Data section (page 55).

      Multiple Exposures

    No adverse health effects are anticipated to result from any exposures identified incompleted exposure pathways 2, 3, and 4 involving West Thorpe Road residents. Residentsin the West Thorpe Road area were potentially exposed to contaminants via three pathways: 2 - TCE in drinking water, 3 - No-Name Ditch and 4 - Tordon. This multiple exposure wasevaluated by adding the estimated doses from each pathway for each contaminant to providean overall estimate of health risk. The additive effects from exposure to contaminantsdetected in each of these pathways did not result in a significant increase in health risk. It isimportant to note that some chemicals can cause more than an additive effect when combined,in which case this assessment will underestimate the potential for adverse health effects. There is little evidence, however, of such synergistic effects between chemicals at levelscommonly found in the environment.

CONCLUSIONS

No apparent public health hazard exists from past exposure of West Thorpe Road area residentsto Tordon detected in drinking water, surface water, soil, and sediment in the West Thorpe Roadarea. Although the cancer-causing ability of Tordon is unclear, the low levels detected are notlikely to pose a significant health hazard.

No apparent public health hazard exists from the combined exposure of West Thorpe Road arearesidents to contaminants detected in completed exposure pathways 2, 3 and 4.

RECOMMENDATIONS

No recommendations are necessary with respect to this pathway.

Pathway 5: On-Base Activities --> Sediment/Soil --> Fairchild Personnel

SUMMARY

Thirty-nine contaminated sites have been identified on base. No apparent public health hazardexists for on-base workers exposed to contaminants in soil, surface water or sediment. No basepersonnel are exposed to contaminated groundwater.

No apparent public health hazard exists for children exposed to lead in surface soil at the formeraircraft salvage yard site (SW-11). The site is currently a recreation area (Warrior Park) and wasfound to contain elevated levels of lead in surface soil with a maximum of 1,340 ppm. Based ona previous DOH recommendation, the base conducted further sampling to determine if thismaximum level was representative of high use areas of the park. This extensive sampling found amaximum of 98 ppm lead in surface soil. Blood lead levels in children exposed to lead inWarrior Park soil are not expected to increase above a level of health concern. The park shouldbe periodically inspected, however, to ensure that sub-surface debris left over from salvageoperations does not become a physical hazard in the future.

BACKGROUND

To date, thirty-nine sites have been investigated for contamination of soil, sediment andgroundwater at the base. Many of these sites contain elevated levels of metals, TPH, and VOCs. The contaminants of concern for this pathway are given in Appendix C, Table 5 along with thebase-wide maximum levels detected. Some sites that are not listed in the table containcontaminants of concern at lower levels. On-base contamination is the result of fuel spills andleaks, discharge of wastes to the storm water drainage system and landfilling. Much of thecontamination was detected below ground surface and represents an exposure pathway only forclean-up workers or those workers involved in projects requiring soil excavation. Other sites,such as the wastewater lagoons (WW-1) and the former fire training area (FT-1), are abandonedor infrequent work areas and do not present opportunities for repeated exposure.

Site IS-3 is the location of the former reciprocating engine test shop that was housed in Building2150. The building operated as an engine test shop from 1942 to 1956 when it was converted toa multi-purpose facility. The main area of concern is in the basement where six transformerswere installed and several others temporarily stored during a base-wide PCB removal. A 8.5-foot deep sump also located in the basement apparently received waste from basement floordrains. Sump sediments and surface water contained low levels of PCBs, SVOCs and metals. Building 2150 was demolished in June 1997. Soil sampling at the site following demolition didnot detect PCBs.

Site SW-11 represents a potential exposure point for base personnel and their children to soilcontaminants while using the recreation facilities located in this area (Warrior Park). This areaincludes a basketball court, a dirt baseball field, and some grass-covered lawn. The site wasformerly used as an aircraft parts salvage and reclamation area from 1945 to 1958. A LimitedField Investigation (LFI) conducted in October 1991 uncovered a considerable amount ofmetallic debris in sub-surface soil. Soil sample analysis conducted during the LFI indicatedelevated levels of lead and cadmium. The LFI also noted several hundred reciprocating enginetest valves buried together under one foot of soil. Six valves were opened, two of which werefound to contain elemental sodium. 34

In March 1992, a layer of soil and grass seed was placed over some portions of the SW-11 siteto prevent contact with metallic debris and contaminants in soil. 35 This action was supported byATSDR as a temporary measure pending further investigation provided the soil cover remainedintact. 36 Later analysis of soil samples taken in March 1993 during the Remedial Investigation(RI) for Priority 2a sites revealed elevated levels of metals in both surface and subsurface soil. The RI also noted metallic debris in surface and sub-surface soil and that approximately 90% of the SW-11 area was unvegetated.

The Draft for Public Comment release of this health assessment in August 1997 concluded thatan indeterminate public health hazard existed for children who played frequently at Warrior Park. A recommendation for further sampling was made in order to better characterize the potentialexposure of children to lead in surface soil at the park. In response to this recommendation, thebase collected 35 surface soil samples at Warrior Park in November 1997. Samples were takenin areas of potentially high exposure (i.e., sparsely covered or bare dirt areas, baseball field) and analyzed for lead.

HEALTH ASSESSMENT

Base-Wide Worker Exposure

Contaminants of concern in on-base soil were assessed using the maximum values detected base-wide given in Appendix C, Table 5. Workers could be exposed to contaminants throughaccidental ingestion of and skin contact with soil and inhalation of dust. Exposure to VOCs insoil could also occur via inhalation of vapors. Exposure via vapor and particulate inhalation was evaluated qualitatively.

    Non-Cancer Effects

Non-cancer health effects are not anticipated to result from workers exposed to contaminantsin on-base surface or sub-surface soil. A dose was calculated for a worker exposed to themaximum levels of VOCs, metals, TPH and PCBs detected in on-base soil resulting fromroutine maintenance or excavation work. A maintenance worker was assumed to contactsurface or sub-surface soil once per week via skin contact and accidental ingestion. A morelikely scenario would be a maintenance worker contacting only surface soil and an excavationworker with access to both surface and sub-surface soil for a short period of time. It is alsoassumed that workers could be exposed to the maximum level of each contaminant of concernregardless of whether these maximums were detected at different sites. This scenario is,therefore, a high estimate of dose that should be protective of both workers.

None of the estimated doses calculated for workers exposed to on-base contaminantsexceeded their respective MRL or RfD. The combined doses also did not exceed a level ofconcern. Considering that the exposure scenario outlined above provides a high estimate ofexposure, this estimate will likely be protective of any added exposure through inhalation ofvapors or dust.

Some contaminants of concern found in on-base soil have no RfDs or MRLs with which tocompare a dose estimate. Of all the inorganic contaminants (metals) of concern that do nothave RfDs or an MRLs, only magnesium was detected consistently above background. A90th percentile value calculated for magnesium in WW-1 lagoon sediments was 3 times higherthan the 90th percentile value derived by Ecology. This elevation is probably due to pastwaste drainage from base maintenance shops that now discharge to a sanitary sewer. Becauselevels of magnesium will not likely increase and the area is not frequented, non-cancer adversehealth effects are not anticipated from exposure to magnesium in on-base soil or sediment.

Alkylbenzenes, 2-methylnaphthalene and 2-hexanone are organic contaminants of concern thatdo not have an RfD or an MRL. Surrogate RfDs were adopted from chemicals with similarstructure in order to compare with resulting doses of these contaminants. The calculateddoses were all well below their respective surrogate RfDs and are not expected to contributesubstantially to the overall estimate for non-cancer risk.

    Cancer Effects

No significant increase in cancer risk is estimated to result from exposure of workers tocontaminants in on-base soil, surface water or sediment. Cancer risk estimates werecalculated for arsenic, 1,1,2,2-tetrachloroethane, benzene, beryllium, methylene chloride, TCEand PCBs. Maximum values of these carcinogens were used to estimate a cancer risk for amaintenance worker exposed once per week for 25 years of employment via accidentalingestion of and skin contact with soil. Of these cancer-causing chemicals only arsenic and1,1,2,2-tetrachloroethane contributed significantly to overall cancer risk. A maximum of2,050 ppm 1,1,2,2-tetrachloroethane was detected in the soil excavated during a tank removalnear Building 2447. A maximum of 258 ppm arsenic was found in a drainage ditch near theflight line. A site-specific evaluation of these areas showed that no other contaminantscontributed significantly to cancer risk.

Cancer risks calculated for the maximum level of arsenic found in a drainage basin near theflight line (SD-38) and 1,1,2,2-tetrachloroethane in the area of the tank excavation at Building2447 (SD-37) were slightly elevated using the above exposure scenario. This scenarioprobably overestimates the actual risk, however, as neither area requires repeated maintenanceactivity. A more realistic exposure would be that of an excavation worker exposed for 30days during a one-time removal action. Exposure of workers during an on-base removalaction is not expected to result in a significant cancer risk because of the shorter exposureduration and required implementation of a health and safety plan.

On-Base Recreators at Warrior Park (SW-11)

The SW-11 site is currently used as a recreation area (Warrior Park) with picnic benches,basketball court and baseball field. The only contaminant of concern at the site is lead in surfacesoil. A maximum of 1,340 ppm of lead was detected in surface soil at the SW-11 site during RIsampling in March 1993. Soil sampling conducted during the RI and previous investigations waslimited, however, and did not include high use areas of the park (e.g., baseball field). InNovember 1997, the base conducted extensive surface soil sampling of high use areas at WarriorPark to better determine the potential exposure of children to lead in soil. A maximum of 98ppm lead in surface soils was detected during this sampling. It was assumed that children couldbe exposed primarily through accidental ingestion of soil and inhalation of dust while playing inthe park.

Also of concern is the presence of debris left over from past aircraft salvage operations thatcould pose a physical hazard. The debris was noted in soil borings taken in March 1993indicating that the soil cover installed in March 1992 was compromised in this area. Furtherinspection of the park in November 1997 noted small amounts of debris in surface soil. Sodiummetal contained in buried reciprocating engine valves will only be a hazard if excavated.

    Non-Cancer Effects

No apparent public health hazard exists for childrenexposed to lead in surface soil at Warrior Park. Themaximum level of lead detected in surface soil at 1,340ppm is not representative of lead levels throughout thepark. Extensive sampling of high use areas of the parkindicate that levels are considerably lower. Exposure tothe maximum level of lead found in the surface soil ofthese high use areas (98 ppm) is not expected tosignificantly elevate blood lead levels in children. EPA'sIntegrated Exposure Uptake Biokinetic Model (IEUBK -Version 0.99D) indicates that blood lead levels in childrenbetween 1 and 6 years of age would not exceed 3.9 ug/dlat this level of exposure. This is well below EPA's actionlevel of 10 ug/dl.

Children between 1 and 2 years of age are most susceptible to increased blood lead levelsresulting from exposure to lead in soil. 37 Evidence exists to indicate that health effects in youngchildren may occur at blood lead levels as low as 6 ug/dl. The most sensitive toxic effect fromlead exposure in children involves behavioral changes resulting from nervous system toxicity. Many of these behavioral changes involve impaired learning ability and include decreasedperformance on IQ tests. 38

    Cancer Effects

EPA has classified lead and its compounds as a Group B2 probable human carcinogen based onsufficient evidence in animals and inadequate evidence in humans. Quantitative carcinogenicanalysis of lead in soil was not possible due to the lack of adequate studies from which to derivea cancer potency factor. The developmental effects of lead in children are recognized as themost sensitive toxic endpoint of lead exposure. The non-cancer assessment discussed above,therefore, should be protective of all health effects.

CONCLUSIONS

No apparent public health hazard exists for workers exposed to contaminants in on-base soil or sediment.

No apparent public health hazard exists for children exposed to lead in surface soil while playingat Warrior Park (SW-11). Debris in surface soil from past salvage operations appears to beminimal and is not expected to pose a physical hazard for recreators in the park unless moredebris is exposed through erosion or excavation. Sodium metal containing engine valves foundin the park will not be a hazard provided they remain below the surface.

RECOMMENDATIONS

A previous recommendation made in the Draft for Public Comment release of this document forfurther soil sampling of Warrior Park was addressed by the base.

The Warrior Park area should be periodically inspected ensure that any debris found in surfacesoil poses no physical hazard. Excavation in the area should be monitored in order to preventunintentional disturbance of the engine valves containing sodium metal.



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